The total trade was worth around $20K and I estimate their error cost me about $170. It was just under a 1% of the trade. Should I complain?

Has anyone ever complained to a brokerage company holding their firm's 401K accounts? Was it worthwhile?Were there ramifications within the company?

Ask nice first, get progressively tougher if need be.

The brokerage firm has a fiduciary responsibility to any qualified plan to cover any losses that occur due to their mistake(s). If there is a gain due to errors, they may not take the gain.If there are both losses and gains attributable to a single error, they may use any gains to offset losses.